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Up Topic Welding Industry / Technical Discussions / Vibratory Stress Relieving
- - By RButler (*) Date 03-07-2007 20:05
We have 24" Carbon steel Elbow fabrications that are fabricated from 516 Gr.70 material. We heat treat these in a oven with a purge gas. Our engineering department is looking into alternate stress relieveing methods. Vibratory stress relieving came up.
My question is. Is this a viable process that has been proven successful or is this a process with an impressive title and unproven results?
Any information will be helpful.

R Butler
Parent - - By jon20013 (*****) Date 03-07-2007 20:16
There has been many discussions here about the viability of this approach.  The sides are almost diabolically opposite.  Keeping a very open mind, I believe there is some benefit to it, although I've never used it personally I've done enough research to believe it isn't all smoke and mirrors.  The one unfortunate thing is is that the stress relieving element of it cannot be used to satisfy Code requirements.  If you are simply looking at it as a means of possibly controlling distortion claims have it that it is useful.  Be very wary about manufacturing literature as virtually all claim significant "mechanical improvements" which I believe have not been adequately verified in spite of supposed testimonials....  Good luck.  You can also go to the Toolbar here in the forum and "Search" and enter the term vibratory stress relief to get additional background from previous postings.
Parent - - By js55 (*****) Date 03-07-2007 21:03
If I may, can I ask what your heat treat regime is and why you are purging? Unless there is something specific to your application, and your looking for ways to economize, this may be a start. There isn't anything inherent to 516-70 that would require a purged heat treat.
Parent - - By aevald (*****) Date 03-07-2007 21:59
Would the purged heat-treat be used to avoid the scaling and oxidation that might be encountered in your heat-treat process? That would be a guess on my part and would that be due to an extended soak at temperature in the treating process? Otherwise, as js55 stated, it would seem rather spendy to go through this type of process. Curious also. Regards, aevald
Parent - - By js55 (*****) Date 03-07-2007 22:26
Allen,
That would really have to be it I suppose. Perhaps a critical application where any scaling or oxidation would be prohibitive. That's what really makes me curious with a carbon steel. But there would be so little scaling in a simple stress relief. More in an annealing or normalizing. But that seems unlikely in a carbon steel. I guess we'll just have to wait and see.
Parent - - By awill4x4 (**) Date 03-08-2007 11:59
We do chassis' repairs on Chrome/Moly 4130 sprintcars here in Australia and one particular brand of sprintcar frames made a lot of noise about their use of vibratory stress relief. Well, we see all the major brands in for repair at one time or another and they all basically seem to break in roughly the same areas regardless of whether they have used vibratory stress relief or not.
Regards Andrew.
Parent - By RButler (*) Date 03-09-2007 16:21
Andrew,
Thanks for the reply. Would you know what kind of equipment is used doing this kind of stress relieving. I am curious to see what a unit looks like that can do this.  As one of the other post messages suggested, I will do a search of this site to see what else turns up

Regards,
Ron B
Parent - - By RButler (*) Date 03-09-2007 14:50
The purge is for cutting down on the scale and oxidation.
Parent - By jon20013 (*****) Date 03-09-2007 15:07
We do the same at our shop.  Although a bit more pricey, it works really well.
Parent - - By js55 (*****) Date 03-09-2007 15:08
R,
I guess, at least from my point of view, that the question qwas one more of curiosity. At least as far a any code or spec compliance is concerned I don't beleive there is any alternatives out there. But it leads to the question: is purging of your product actually necessary to its application. I'm just curious. HT of course oxidizes surfaces but in most instances it doesn't matter or the material will undergo a final coating that renders the oxidation irrelevent. For example blasting, wheelabrator, etc., processes, which are cheaper than purging HT's.
Parent - - By js55 (*****) Date 03-09-2007 15:09
Kleerlee mah spelin'n typin iz atroshus.
Parent - - By jon20013 (*****) Date 03-09-2007 15:19
Jeff, in our case, purging of our product is usually not necessary to its application but there are some specifications that won't allow us to blast afterwards and in some cases we've found it more cost effective to use the purging in lieu of paying additional labor rates.
Parent - - By js55 (*****) Date 03-09-2007 15:30
JOn,
Do you guys use Argon? And if I may ask, how big is your furnace?
Parent - By jon20013 (*****) Date 03-09-2007 17:03
Jeff;

We do not have a furnace, but instead contract out all of our heat treat at the moment.
Parent - By RButler (*) Date 03-09-2007 18:41
The heat treat facility we use uses nitrogen to purge the ovens.
Parent - - By G.S.Crisi (****) Date 03-09-2007 16:18
js55,
just a curious question: are you from Dixie? Dixielanders use to say Ah instead of I, Mah instead of My and so on.
Giovanni S. Crisi
Parent - By js55 (*****) Date 03-09-2007 16:54
Giovanni,
I"m LMAO!!! I spent a few years in Virginia, a few years in SC and am now in Houston. Ah picked up a few things but ah just couldn't seem to communicate with these texans very well.
Ah was headin along I10 west of Houston and stopped off at a place called Buck'E's. Some of ya'll may know it. Ah purchased me a copy of a Texan to English Dictionary and the rest was history.
Now these folks all know what ahm sayin.
Parent - - By RButler (*) Date 03-09-2007 16:42
The  purging  of this fabrication helps keep the oxidation down  as I said before. The inside of these elbow require a very smooth finish after heat treat. The less scale the easier it is to polish the inside.

Regards,
Ron B
Parent - - By js55 (*****) Date 03-09-2007 17:30
Are the elbows being cold formed and fusion welded?
Parent - By RButler (*) Date 03-10-2007 11:40
The elbows are fusion welded, we do some here and some are purchased from an outside vendor.

RB
Up Topic Welding Industry / Technical Discussions / Vibratory Stress Relieving

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